Multi-axis force sensors are generally used in order for a robot to move according to a person's intention when the robot and the person work together, and are widely used in order for the robot to move based on force control in assembly or various works using the robot's hands. For example, a multi-axis force sensor is applied to a medical robot in order to feed back the contact force of a tool, which is used for a micro-invasive operation, into a user. In addition, a multi-axis force sensor is applied to the ankle of a humanoid robot or the sole of humanoid robot's foot in order to control the balance of the robot, or is applied to the palm of humanoid robot's hand in order for the robot to stably come into contact with an object when lifting the object.
In recent years, these multi-axis force sensors have been increasingly utilized in various fields. For example, the multi-axis force sensors are utilized in wearable robots, wearable devices, IOT (Internet of things) devices, etc.
Conventionally, three types of multi-axis force sensors are mainly utilized. Specifically, they are a series-stacked multi-axis force sensor, a parallel manipulator multi-axis force sensor, and a monolithic multi-axis force sensor. Here, 1) the series-stacked multi-axis force sensor is a force sensor in which single-axis elastic bodies are arranged in series, 2) the parallel manipulator multi-axis force sensor is a force sensor in which the joint portion of a parallel manipulator having three degrees of freedom or six degrees of freedom is replaced with a flexure joint, and 3) the monolithic multi-axis force sensor is a force sensor designed such that an elastic body has a slit or spoke shape.
However, these conventional multi-axis force sensors are problematic in that a complicated calibration process is required to estimate each axial force, there is a limit to miniaturization, and an error occurs due to axial interference of 3 to 5% caused when each axial force is measured.
Accordingly, it is necessary to develop a new multi-axis force sensor in order to resolve the above problems.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.